Hey guys, I have a question for you who are running cool heads on your LT500: What cc dome are you running in it? It would also help if you told me what mods you have on your quad... You see I grenaded my motor again last Sunday. This time the base gasket held up, but one of the bearings in the clutch basket came apart and the crank bearings are also toast... The one from the clutch basket worked up through the cylinder and mangled the head and piston so it looks like I now have a good excuse to get a cool head. Just don't know what cc dome would be good for it though. Thanks!

 

Dirtgirl, stay clear of the cool head. The stock head is much better. I've made my case earlier in this forum. If you can't find it I will write it again. I'm just saying it's not worth it.

 

I'll agree! The CoolHead isn't worth the $$$$. They sell you a 'one size fits all' application. Yes, you can get diff. cc domes, but the stocker can be machined to work really well for very little scratch.
If yours is torn up really bad, you might get lucky to find one really cheap on ebay...

I've got a brand new cool head I'd sell really cheap! (Fits the '87) Can't remember the dome size... but I'd guess around 54cc (Custom cut)

 

How much you want for yours?

 

Geez, I dunno.... I'll have to go see what I paid... I see 'em on Ebay for $220
Mine only has one ride on it... less than 2 hrs.

The only issue is... the stud holes are enlarged to handle 3/8 studs... I can't remember what studs you put back in your cylinder?

Make me an offer?

 

Oh... there's also a stocker on Ebay right now... I think the bidding is at $35 for it... looks like a parts/junk dealer..
Might be worth a look?

 

How did a bearing from the clutch basket get into the cylinder? they are two different areas. totally isolated. maybe it was a crank bearing that hammered the piston/head. I have a 51cc dome and haven't had any problems with it. They do hold more coolant than stock which should let you run higher comp with the same octane fuel due to lower temp. not to mention that when you mill you stock head you have to reshape the squish area which costs more $. So in the long run you get a head that you can change domes, more coolant capacity, and best of all o-rings so you won't blow anymore head gaskets.

It runs about 215psi. with the 51cc dome. The exh. port is raised pretty high which will bring the cyl. cranking press. down. That head on a stock unported cylinder would have a much higher unusable pressure.

 

The squish and bowl on the stock head are shaped perfect. The only thing you have to do is cut about .015 off of the gasket surface to bring the squish clearance to what you want. That puts you at around 12.5:1 compression ratio; good for pump gas. Also the stock head runs the water over the chamber. The cool head is just a bigger volume of non flowing water. Plus if the cool head don't use a gasket then how does it restrict the water by the inlet and outlet to evenly rout water?
However, it does look better than stock.

 

I don't know either.. Find out what you paid and then decide what you want for it and let me know.. The holes in the head will work just fine for mine - I put straight 10mm in it which is .3937" 3/8 is .375"...

 

The stock head can work good. Theres no doubt about that. The cool head like the stock head when machined for an o-ring has the coolant passages partially closed off to direct water to the right area, or you can use a stainless o-ring like cars do with a copper head (Tudors) gasket which also has the restrictions in it. The problem I had was after porting, my cyl. press. was way down due to the increased exh. duration. It would take a whole lot more than .015 to bring the comp. back to even stock. We all know there is a gain from running more comp., and if it takes race gas then thats what it takes. If you shave off the amount needed to get 51cc's you start milling into the squish band making it's diameter smaller which will require remachining. If you want a little more perf. then just mill the head, but if you want more then you're going to have to address some other issues. My cool head also runs water over the chamber only more of it. It doesn't look much better, I painted it Suz. blue. Stock you know.